Mounting assembly for a steerable wheel with variable track width

ABSTRACT

A wheel-mounting assembly for a utility vehicle includes a chassis and a wheel support assembly mounted to respective outboard ends of first and second telescopic axle assemblies. The first and second telescopic axle assemblies are laterally spaced from one another and are each secured to the chassis. The first and second telescopic axle assemblies each include a respective actuator arranged to control extension and retraction thereof for steering and track-width control.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims the benefit of the filing date of U.S.Provisional Patent Application 62/772,215, “Mounting Assembly for aSteerable Wheel with Variable Track Width,” filed Nov. 28, 2018, theentire disclosure of which is incorporated herein by reference.

FIELD

The disclosure relates to utility vehicles having variable track width,such as agricultural row crop sprayers and spreaders. In particular, thedisclosure relates to a steering mechanism for steerable wheels mountedto such vehicles that also facilitates variable track-widthfunctionality.

BACKGROUND

Some agricultural vehicles are configured to be operated in fields amongrow crops. Application machines such as self-propelled or trailedsprayers, for example, may have wheels configured to pass between croprows and a spray boom that extends outwardly from the vehicle to spraythe crop as the machine travels through the field. In order to avoiddamaging the crops as the vehicle moves through the field, each of thewheels must have the proper width to travel between the rows, and thetrack width (the lateral distance between the wheels) must match rowspacing or predefined “tramlines” so that the wheels do not damage thegrowing crop.

Many agricultural sprayers on the market today offer functionality tochange the track width to meet the requirements of the task in hand.Various different mechanisms exist to deliver this functionality. Oneknown system involves wheel support assemblies being mounted to avehicle chassis by a telescopic mechanism. U.S. Pat. No. 9,290,074,“Machine Suspension and Height Adjustment,” issued Mar. 22, 2016,discloses such a telescopic arrangement, the contents of which areincorporated herein by reference. FIG. 5 of U.S. Pat. No. 9,290,074shows a telescoping axle arrangement with an outer axle 28 secured to achassis and an inner axle 30 slidingly engaged with the outer axleallowing the wheel to shift transversely relative to the longitudinalaxis of the chassis. The outer axle and inner axle support the weight ofthe chassis on the wheel. The wheel is carried on a wheel supportassembly which is pivotably mounted to an outboard end of the inner axleto permit steering movement. U.S. Pat. No. 9,290,074 further discloses,such as in FIGS. 22 through 26, a steering actuator 416 mounted to theinner axle to control steering of the wheel.

BRIEF SUMMARY

In accordance with one aspect of the disclosure, a wheel-mountingassembly for a utility vehicle comprises a chassis, a wheel supportassembly, and first and second telescopic axle assemblies. The wheelsupport assembly is mounted to respective outboard ends of the first andsecond telescopic axle assemblies. The first and second telescopic axleassemblies are laterally spaced from one another and are each secured tothe chassis. The first and second telescopic axle assemblies eachcomprise an actuator arranged to control extension and retraction of theaxles assemblies for both steering and track width control.

The disclosure combines a track width adjustment mechanism with asteering mechanism thereby advantageously eliminating the need fordedicated steering apparatus and saving on part count and assembly cost.The dual telescopic axle arrangement also provides improved robustnessin construction and operation as compared to a single-axle arrangement.

In one embodiment, the first and second axle assemblies are alignedparallel to one another so that simultaneous extension or retraction ofthe telescopic axle assemblies (during track width adjustment forexample) does not alter the spacing at the outboard ends, thusmaintaining a constant steering angle.

In one embodiment, the outboard end of the first axle assembly iscoupled to the wheel support assembly by a link arm, which is connectedat a first end to the first axle assembly by a first pivotableconnection and at a second end to the wheel support assembly by a secondpivotable connection. The outboard end of the second axle assembly iscoupled to the wheel support assembly by a third pivotable connection.One of the first and second pivotable connection may comprise aball-and-socket joint to facilitate free angular movement of the wheelsupport assembly.

In one embodiment, at least one of the first and second telescopic axleassemblies comprises an outer axle portion fixed to the chassis, and aninner axle portion slideably received by the outer axle portion. Theouter axle portion may comprise a plurality of bearings secured withinan outer tube, wherein the bearings receive and support the inner axleportion in a sliding relationship. The outer tube may be of a square orcircular section. The bearings may each comprise an adjustable pillowblock that allows for adjustment in response to wear over time.

In one arrangement, the inner axle portion comprises a hydraulicactuator. Advantageously, this provides a compact arrangement whereinthe actuator is integrated into the envelope of the outer axle portion.The hydraulic actuator comprises a piston that is preferably connectedto the outer axle portion or chassis. As such, forces from the hydraulicactuator are exerted directly between the chassis and the wheel-mountingassembly.

In an alternative embodiment the inner axle portion comprises a tubularmember, and the respective actuator comprises a hydraulic actuatorconnected between the tubular member and the outer axle portion. Thehydraulic actuator may be mounted to an outside surface of the tubularmember. Although not as compact as certain embodiments, this arrangementprovides for greater accessibility to the actuator for servicing.

The actuators may be, for example, electric or pneumatic actuators.

The disclosure lends itself well to utility vehicles and especiallythose adapted for use in agriculture for applying inputs to crops, suchas sprayers and spreaders. In particular, the disclosure is well suitedto implementation in sprayers and spreaders having high-clearance liftmechanisms associated with the wheel support assemblies.

In one example implementation of the disclosure in a utility vehicle, asteering control system is provided and arranged to control steeringmovement of the wheel support assembly with respect to the chassis. Inresponse to steering control commands, the steering control system isconfigured to simultaneously extend a first of the actuators and retracta second of the actuators so as to pivot the wheel support assemblyaround a steering axis. Using the same hardware, the track width may beincreased in response to a track-increase command, wherein the steeringcontrol system is configured to simultaneously extend both actuators soas to move the wheel support assembly further from the chassis.Conversely, the track width may be decreased in response to atrack-decrease command, wherein the steering control system isconfigured to simultaneously retract both actuators so as to move thewheel support assembly closer to the chassis.

BRIEF DESCRIPTION OF THE DRAWINGS

While the specification concludes with claims particularly pointing outand distinctly claiming what are regarded as embodiments of the presentdisclosure, various features and advantages of embodiments of thedisclosure may be more readily ascertained from the followingdescription of example embodiments of the disclosure when read inconjunction with the accompanying drawings, in which:

FIG. 1 is a perspective view of a portion of an agricultural sprayer,shown with two of the wheels omitted to illustrate the wheel-mountingassemblies;

FIG. 2 is a perspective view of the front right wheel-mounting assemblyof the sprayer of FIG. 1 ;

FIG. 3 is a perspective view of the wheel-mounting assembly of FIG. 2shown with one outer tube omitted to reveal otherwise-hidden componentsof a telescopic axle assembly thereof;

FIG. 4 is a schematic plan view of an outboard end of the wheel-mountingassembly of FIG. 2 illustrating a linkage arrangement between the axleassemblies and the wheel support assembly;

FIG. 5 is a view of a vertical section along the line V-V shown in FIG.3 ;

FIG. 6 is a schematic diagram of part of a steering control system forcontrolling steering and track-width adjustment in conjunction with thewheel-mounting assembly of FIG. 2 ;

FIG. 7 is a simplified block diagram of the steering control system ofFIG. 6 ;

FIG. 8 is a perspective view of another wheel-mounting assembly; and

FIG. 9 is a view of a vertical section along the line IX-IX shown inFIG. 8 .

DETAILED DESCRIPTION

All references cited herein are incorporated herein in their entireties.If there is a conflict between definitions herein and in an incorporatedreference, the definition herein shall control.

The illustrations presented herein are not actual views of any header orportion thereof, but are merely idealized representations that areemployed to describe example embodiments of the present disclosure.Additionally, elements common between figures may retain the samenumerical designation.

The following description provides specific details of embodiments ofthe present disclosure in order to provide a thorough descriptionthereof. However, a person of ordinary skill in the art will understandthat the embodiments of the disclosure may be practiced withoutemploying many such specific details. Indeed, the embodiments of thedisclosure may be practiced in conjunction with conventional techniquesemployed in the industry. In addition, the description provided belowdoes not include all elements to form a complete structure or assembly.Only those process acts and structures necessary to understand theembodiments of the disclosure are described in detail below. Additionalconventional acts and structures may be used. Also note, the drawingsaccompanying the application are for illustrative purposes only, and arethus not drawn to scale.

As used herein, the terms “comprising,” “including,” “containing,”“characterized by,” and grammatical equivalents thereof are inclusive oropen-ended terms that do not exclude additional, unrecited elements ormethod steps, but also include the more restrictive terms “consistingof” and “consisting essentially of” and grammatical equivalents thereof.

As used herein, the term “may” with respect to a material, structure,feature, or method act indicates that such is contemplated for use inimplementation of an embodiment of the disclosure, and such term is usedin preference to the more restrictive term “is” so as to avoid anyimplication that other, compatible materials, structures, features, andmethods usable in combination therewith should or must be excluded.

As used herein, the term “configured” refers to a size, shape, materialcomposition, and arrangement of one or more of at least one structureand at least one apparatus facilitating operation of one or more of thestructure and the apparatus in a predetermined way.

As used herein, the singular forms following “a,” “an,” and “the” areintended to include the plural forms as well, unless the context clearlyindicates otherwise.

As used herein, the term “and/or” includes any and all combinations ofone or more of the associated listed items.

As used herein, spatially relative terms, such as “beneath,” “below,”“lower,” “bottom,” “above,” “upper,” “top,” “front,” “rear,” “left,”“right,” and the like, may be used for ease of description to describeone element's or feature's relationship to another element(s) orfeature(s) as illustrated in the figures. Unless otherwise specified,the spatially relative terms are intended to encompass differentorientations of the materials in addition to the orientation depicted inthe figures.

As used herein, the term “substantially” in reference to a givenparameter, property, or condition means and includes to a degree thatone of ordinary skill in the art would understand that the givenparameter, property, or condition is met with a degree of variance, suchas within acceptable manufacturing tolerances. By way of example,depending on the particular parameter, property, or condition that issubstantially met, the parameter, property, or condition may be at least90.0% met, at least 95.0% met, at least 99.0% met, or even at least99.9% met.

As used herein, the term “about” used in reference to a given parameteris inclusive of the stated value and has the meaning dictated by thecontext (e.g., it includes the degree of error associated withmeasurement of the given parameter).

With reference to FIG. 1 , a self-propelled agricultural sprayer 10 mayinclude a frame or chassis 12, a driver's cab 14, a storage tank 16, anda spray boom assembly 17 for applying liquid plant-protection products.Although only one wheel 18 is shown in FIG. 1 , four wheels 18 aretypically mounted to the chassis 12 by respective wheel-mountingassemblies 20, which are constructed in accordance with principles ofthe disclosure and will be described in more detail below.

Although an agricultural row crop sprayer 10 is illustrated, thedisclosure can be applied to other agricultural utility vehicles,especially those having high-clearance lift mechanisms that carry thechassis at sufficient height to prevent damage to row crops over whichthe chassis travels. Other examples of utility vehicles to which thedisclosure can be applied, by way of example only, includeself-propelled material spreaders including air spreaders for granularfertilizer. Furthermore, the disclosure is not limited to self-propelledmachines, and may also be applied to steerable trailed implements forexample, especially those used in agriculture but not exclusively so.Neither is the disclosure limited to agricultural vehicles, but may findapplication in other fields.

Before a more detailed description of the wheel-mounting assemblies 20is given, the principals of high-clearance lift mechanisms will bebriefly discussed to provide a more complete understanding of thesprayer 10 illustrated. With reference to both FIGS. 1 and 2 , eachwheel-mounting assembly 20 includes a wheel support assembly 22. Eachwheel-mounting assembly 20 in the illustrated embodiment may be the samefor each and every wheel, but reference will be made to the singularonly hereinafter.

Each wheel support assembly 22 includes a hub portion 24, which carriesa drive motor 26 (shown in FIG. 1 only) drivingly connected to the wheel18. The drive motor 26 may be hydraulic or electric and derives itspower from a prime mover located on the chassis 12. The motor 26 rotatesto provide forward and reverse propulsive forces to the wheels 18 in aknown manner.

Each wheel support assembly 22 may be provided with a mechanism tofacilitate vertical height adjustment of the chassis 12 with respect tothe hub portion 24 and the associated wheel 18. U.S. Pat. No. 9,290,074,incorporated by reference above, discloses a number of examples ofmechanisms to provide the variable height functionality of the wheelssupport assemblies 22.

It should be appreciated that the wheel support assembly 22 illustratedin the drawings is merely one example, and the precise constructionthereof may vary. Furthermore, the disclosure is also applicable toutility vehicles without variable height functionality. In essence, thewheel support assembly 22 provides a rigid structure to which a wheelcan be mounted to support the chassis 12. Although the wheel supportassembly 22 may allow for vertical adjustment of the supported wheel 18with respect to the chassis 12, the transverse position of the wheelsupport assembly 22 with respect to the chassis 12 dictates the trackseparation and steering angle of the wheel 18.

Turning to the construction of the wheel-mounting assembly 20, the wheelsupport assembly 22 is mounted to outboard ends 28 of first and secondtelescopic axle assemblies 31, 32. Each telescopic axle assembly 31, 32is elongate and extends transversely between the chassis 12 and theassociated wheel support assembly 22.

First telescopic axle assembly 31 is laterally spaced from secondtelescopic axle 32, forwardly thereof with respect to the direction oftravel of sprayer 10. In other words, the first telescopic axle assembly31 is disposed in front of the second telescopic axle assembly 32. Asbest seen in FIGS. 2 and 3 , the telescopic axle assemblies 31, 32 arealigned parallel to one another in a side-by-side relationship. However,it is envisaged that steering and track width functionality providedthereby can also be delivered with an alternative construction in whichthe telescopic axle assemblies are not aligned parallel to one another.

Both telescopic axle assemblies 31, 32 are secured to the chassis 12 bysuitable attachment mechanisms which provide a rigid and fixedstructural relationship. In one example, a cut out may be provided in alongitudinal beam of chassis 12 to accept the telescopic axle assemblies31, 32 which are then fixed in place by welding or bolting. The firstand second telescopic axle assemblies 31, 32 may also be secured to oneanother at a distance from the chassis to provide suitable rigidity. Anexample of this is illustrated in FIGS. 2 and 3 , in which an end plate34 is secured between both axle assemblies 31, 32 to provide rigidity.

Each of the axle assemblies 31, 32 includes an outer axle portion 31 a,32 a and an inner axle portion 31 b, 32 b. Each inner axle portion 31 b,32 b is slideably received by the associated outer axle portion 31 a, 32a in a telescoping manner. The sliding relationship is along the axis ofthe axle assembly 31, 32 and provides for extension and retraction ofthe axle assemblies 31, 32 which, in turn, allows for the control ofboth steering and track-width adjustment, which will be described inmore detail below. Each outer axle portion 31 a, 32 a may comprise atubular member of square cross-section secured to the chassis 12. Insidethe tubular members may be disposed bearing blocks 35, of which threeare shown in FIGS. 3 and 5 . The bearing blocks 35 are secured by knownmeans inside the respective tubular members. In alternative, embodimentsmore or fewer than three bearing blocks may be present.

The inner axle portions 31 b, 32 b are slidingly received in therespective sets of bearing blocks 35 so as to allow for telescopingextension and retraction with respect to the outer axle portions 31 a,32 a.

In this illustrated embodiment, each of the inner axle portions 31 b, 32b comprises part of a hydraulic actuator 41, 42. Best seen in FIGS. 3and 5 , each of the first and second hydraulic actuators 41, 42comprises a piston rod 41 a, 42 a slidingly received in a cylindricalhousing, which forms the inner axle portions 31 b, 32 b. The cylinderhousings that form the inner axle portions 31 b, 32 b are slidinglyreceived and supported by the bearing blocks 35. Each piston rod 41 a,42 a extends from the associated cylinder housing in a transversedirection towards the chassis 12. The piston rods 41 a, 42 a are coupledindirectly to the chassis 12 via outer axle portions 31 a, 32 a by a pinconnection 43. Alternatively, the piston rods 41 a, 42 a may be coupleddirectly to the chassis 12.

In an alternative embodiment that is not illustrated, the actuators maybe ‘reversed’ wherein the cylinder housing is mounted in a fixedpositional relationship to the chassis 12 and the piston rods form theinner axle portions that are supported on bearings and upon which thewheel support assembly 22 is mounted.

Turning back to the illustrated embodiment, it will appreciated fromFIGS. 3 and 5 that extension and retraction of the hydraulic actuators41, 42 causes the inner axle portions 31 b, 32 b to telescope out of andinto the outer axle portions 31 a, 32 a as the piston rods 41 a, 42 aexert a force upon the chassis 12.

The outboard end of each of inner axle portions 31 b, 32 b is providedwith a respective clevis 45, 46 secured to the end of the cylinderhousing or integrated therewith. The wheel support assembly 22 ismounted to the devises 45, 46 as is best seen in FIGS. 3 and 4 .

Clevis 45 on the outboard end of the first axle assembly 31 is coupledto the wheel support assembly 22 via a link arm 48. The link arm 48 ispivotally connected to the first axle assembly 31 by a first pivotableconnection 50 provided by a pin inserted through the clevis 45. Link arm48 can thus pivot with respect to first inner axle portion 31 b aroundpin 50. The link 48 is connected at a second end to the wheel supportassembly 22 by a ball-and-socket joint 52. Joint 52 includes a ball 52 awhich is integral with a collar 54 that is fixed to an upright 55 ofwheel support assembly 22. Joint 52 also includes a socket 52 b which isintegrally formed in the second (outboard) end of link arm 48. Firstpivotable connection 50 and ball-and-socket joint 52 provide a dual axishinge connection between the first axle assembly 31 and the wheelsupport assembly 22.

In an alternative embodiment, the ball joint 52 is replaced with a pinjoint.

Turning back to the illustrated embodiment, clevis 46 provided on theoutboard end of second axle assembly 32 is coupled to the wheel supportassembly 22 by a third pivotable connection 60, which is provided by apin inserted through the clevis 46. In more detail, a crank arm 62 isrigidly connected to the wheel support assembly 22 extending towards thechassis 12 and serves as an attachment point for the second axleassembly 32. The pin provides the pivotable connection 60 and couplesthe crank arm to the clevis 46.

The wheel support assembly 22 is, therefore, mounted upon the outboardends of first and second telescopic axle assemblies 31, 32 by pivotablejoints 50 and 60. These joints support the weight or load of the vehicle10 upon the wheel support assembly 22 and are constructed withsufficient strength and robustness accordingly. Thus, each of thepivotable joints 50 and 60 and the telescopic axle assemblies 31, 32 maybe load-bearing, and may transfer weight of the chassis 12 to the wheelsupport assembly 22. Extension and retraction of axle assemblies 31, 32is used to control the steering angle of the wheel support assembly 22with respect to chassis 12. With reference to FIG. 4 arrows ‘A’illustrate the direction of extension and retraction.

Turning to FIGS. 6 and 7 , the sprayer 10 includes a steering controlsystem 100 arranged to control steering movement of the wheel supportassemblies 22 with respect to the chassis 12. A steering control unit 70is electrically connected to two directional control valves 71, 72 thateach serve to control the delivery of pressurized hydraulic fluid tocylinders 41, 42. FIG. 6 shows a simplified schematic hydraulic circuitassociated with one wheel support assembly 20. The steering control unit70 may also be connected to further hydraulic control valves forsteering of the other wheels 18.

The steering control unit 70 is in communication with an electroniccontrol unit (ECU) 80 via a data bus 82, either in a wired or wirelessconnection. A steering angle sensor 84 (FIG. 7 ) is in electricalcommunication with ECU 80. The steering angle sensor 84 detects thereal-time steering orientation of wheel support assembly 22. In oneembodiment, the steering angle sensor 84 includes a sensor associatedwith each of the two hydraulic actuators 41, 42 to detect the actual orrelative positions of the piston arms 41 a, 42 a. The steering angle mayfor example may be derived from measuring the absolute positions of bothhydraulic actuators 41, 42.

The ECU 80 comprises control circuitry which may be embodied ascustom-made or commercially available processor, a central processingunit, or an auxiliary processor among several processors, asemi-conductor based micro-processor (in the form of a microchip), amacro processor, one or more application-specific integrated circuits, aplurality of suitably configured digital logic gates, and/or otherwell-known electrical configurations comprising discrete elements bothindividually and in various combinations to coordinate the overalloperation of the sprayer 10.

The ECU 80 further comprises memory. The memory may include any one of acombination of volatile memory elements and non-volatile memoryelements. The memory may store a native operating system, one or morenative applications, emulation systems, emulated applications for any ofa variety of operating systems and/or emulated hardware platforms,emulated operating systems, etc. For example, control of the actuators41, 42 may be implemented through software or firmware executing on aprocessor of the control circuitry. The memory may be separate from theECU, or may be omitted.

A user interface device 86 may be in communication with the ECU 80 andmay generate steering control commands and track-change commands inresponse to a user input. For example, the user interface 86 may includea steering wheel, buttons, and/or joysticks.

Turning back to FIG. 4 , in response to steering control commands, thesteering control system 100 is configured to simultaneously extend oneof the hydraulic actuators 41, 42 and retract the other of the actuators41, 42 so as to cause pivoting of the wheel support assembly 22 (and thewheel 18) around a steering axis which may be positioned at ‘5’. Theposition of steering axis ‘5’ may change depending upon the relativeextension and retraction movements of cylinders 41, 42. In other words,although a steering axis ‘5’ proximate to the center line of wheel 18 ispreferred, the position of steering axis ‘5’ may be altered by varyingthe relative movements of cylinders 41, 42. For example, if the steeringcontrol system 100 maintains the second hydraulic actuator 42 in aconstant position while controlling first hydraulic actuator 41 to steerthe wheel 18, the steering axis ‘5’ would be coincident with the thirdpivotable joint provided around pin 60.

The steering control system 100 is also utilized to adjust the trackwidth of sprayer 10 in response to track-adjustment commands receivedvia user interface 86. For example, in response to a track-increasecommand, the steering control system 100 causes both hydraulic actuators41, 42 to simultaneously extend, thus pushing wheel support assembly 22further from chassis 12. Conversely, in response to a track-decreasecommand, the steering control system 100 causes both hydraulic actuators41, 42 to retract. During adjustment of the track width, it should beappreciated that the steering angle may be kept constant while thevehicle is in motion.

The ECU 80 may be programmed with steering control algorithms to respondto steering control commands in a number of different ways which will beapparent to a person skilled in the art. In addition to manual steeringcontrol with signals received directly from an operator as mentionedabove, the steering control system 100 may optionally operate in anautomatic mode in response to automatically-generated guidance signals.

With reference to FIGS. 8 and 9 , a second embodiment is illustrated inwhich the internal actuators 41, 42 of the first embodiment are replacedwith external actuators 141, 142. In this embodiment, the inner axleportions each include tubular members 131 b, 132 b slidingly received inadjustable pillow blocks 135 secured inside outer axle portions 131 a,132 a. The outer axle portion 131 a, 132 a are again of a square crosssection, and the inner axle 131 b, 132 b are of a circular crosssection.

The adjustable pillow blocks 135 each include a lower portion 135 a andan upper portion 135 b. Screw adjustable members 136 are threaded in tothe underside of outer axle portions 131 a, 132 a and are tightened asrequired through the lifetime of the bearing blocks 135 so as to adjustfor wear. The adjustable pillow blocks 135 may also be employed in theembodiment shown in FIGS. 2 through 6 , replacing the conventionalbushing blocks 35.

Turning back to FIG. 8 , the first hydraulic actuator 141 is connectedon an external side of telescopic axle assembly 131 and is coupledbetween the tubular inner axle portion 131 b at connection 133 and theouter axle portion 131 a at connection 139. The second hydraulicactuator 142 is connected to the second telescopic axle assembly 132 ina similar manner.

Extension and retraction of hydraulic cylinders 141, 142 is controlledby the steering control unit 70 in a similar manner to that describedabove and, as such, controls extension and retraction of first andsecond telescopic axle assemblies 131, 132 to control steering andtrack-width adjustment.

Although the wheel support assembly 22 is not shown in FIG. 8 , itshould be understood that suitable pivotable connections providedbetween the inner axle portions 131 b, 132 b and the wheel supportassembly can be achieved using mechanisms known in the art or thoseshown and described above.

In summary, a wheel-mounting assembly for high-clearance utilityvehicles, especially agricultural applicator machines, may be used foreach or only some of the steerable wheels on the vehicle, wherein eachwheel-mounting assembly shares a similar construction and controlsystem.

Additional non-limiting example embodiments of the disclosure aredescribed below.

Embodiment 1

A wheel-mounting assembly for a utility vehicle comprising a chassis,the wheel-mounting assembly comprising first and second telescopic axleassemblies laterally spaced from one another and each secured to thechassis, wherein the first and second telescopic axle assemblies eachcomprise an actuator arranged to control extension and retraction of arespective telescopic axle assembly; and a wheel support assemblymounted to outboard ends of each of the first and second telescopic axleassemblies.

Embodiment 2

The assembly of Embodiment 1, wherein the first and second telescopicaxle assemblies are aligned parallel to one another.

Embodiment 3

The assembly of Embodiment 1 or Embodiment 2, wherein the outboard endof the first axle assembly is coupled to the wheel support assembly by alink arm which is connected at a first end to the first telescopic axleassembly by a first pivotable connection and at a second end to thewheel support assembly by a second pivotable connection, and theoutboard end of the second telescopic axle assembly is coupled to thewheel support assembly by a third pivotable connection.

Embodiment 4

The assembly of Embodiment 3, wherein one of the first pivotableconnection and the second pivotable connection comprises aball-and-socket joint.

Embodiment 5

The assembly of any one of Embodiment 1 through Embodiment 4, wherein atleast one of the first and second telescopic axle assemblies comprisesan outer axle portion and an inner axle portion slideably received bythe outer axle portion.

Embodiment 6

The assembly of Embodiment 5, wherein the outer axle portions of each ofthe first and second telescopic axle assemblies are fixed to thechassis.

Embodiment 7

The assembly of Embodiment 5 or Embodiment 6, wherein the outer axleportions each comprise a plurality of bearings secured within an outertube, wherein the bearings receive and support a respective inner axleportion in a sliding relationship.

Embodiment 8

The assembly of Embodiment 7, wherein the bearings each comprise anadjustable pillow block.

Embodiment 9

The assembly of any one of Embodiment 5 through Embodiment 8, whereinthe inner axle portion comprises a portion of a hydraulic actuator.

Embodiment 10

The assembly of Embodiment 9, wherein the hydraulic actuator comprises apiston connected to the outer axle portion or the chassis.

Embodiment 11

The assembly of any one of Embodiment 5 through Embodiment 10, whereinthe inner axle portion comprises a tubular member, and wherein therespective actuator comprises a hydraulic actuator connected between thetubular member and the outer axle portion.

Embodiment 12

The assembly of Embodiment 11, wherein the hydraulic actuator is mountedto an outside surface of the tubular member.

Embodiment 13

The assembly of any of Embodiment 1 through Embodiment 12, wherein eachof the first and second telescopic axle assemblies are configured totransfer a portion of a weight of the chassis to the wheel supportassembly.

Embodiment 14

The assembly of any of Embodiment 1 through Embodiment 13, wherein thefirst telescopic axle assembly is rigidly fixed to the second telescopicaxle assembly.

Embodiment 15

A utility vehicle comprising a chassis and a plurality of thewheel-mounting assemblies of any of Embodiment 1 through Embodiment 14.

Embodiment 16

The utility vehicle of Embodiment 15, further comprising a steeringcontrol system arranged to control steering movement of the wheelsupport assembly with respect to the chassis, wherein, in response to asteering control command, the steering control system is configured tosimultaneously extend a first of the actuators and retract a second ofthe actuators so as to pivot the wheel support assembly around asteering axis.

Embodiment 17

The utility vehicle of Embodiment 16, wherein, in response to atrack-increase command, the steering control system is configured tosimultaneously extend both actuators to move the wheel support assemblyfurther from the chassis.

Embodiment 18

The utility vehicle of any one of Embodiment 15 through Embodiment 17,wherein the utility vehicle comprises a self-propelled agriculturalsprayer.

Embodiment 19

A method of adjusting a track width of a utility vehicle comprising atleast a first wheel-mounting assembly of any one of Embodiment 1 throughEmbodiment 14 and a second wheel-mounting assembly of any one ofEmbodiment 1 through Embodiment 14, the method comprising extending eachof the actuators of the first and second telescopic axle assemblies ofthe first wheel-mounting assembly simultaneously, and extending each ofthe actuators of the first and second telescopic axle assemblies of thesecond wheel-mounting assembly simultaneously.

Embodiment 20

The method of Embodiment 19, further comprising maintaining the firstand second telescopic axle assemblies of the first wheel-mountingassembly parallel to one another, and maintaining the first and secondtelescopic axle assemblies of the second wheel-mounting assemblyparallel to one another.

While the present disclosure has been described herein with respect tocertain illustrated embodiments, those of ordinary skill in the art willrecognize and appreciate that it is not so limited. Rather, manyadditions, deletions, and modifications to the illustrated embodimentsmay be made without departing from the scope of the disclosure ashereinafter claimed, including legal equivalents thereof. In addition,features from one embodiment may be combined with features of anotherembodiment while still being encompassed within the scope ascontemplated by the inventors. Further, embodiments of the disclosurehave utility with different and various machine types andconfigurations.

What is claimed is:
 1. A wheel-mounting assembly for a utility vehiclecomprising a chassis, the wheel-mounting assembly comprising: first andsecond telescopic axle assemblies laterally spaced from one another andeach secured to the chassis, wherein the first and second telescopicaxle assemblies each comprise an actuator arranged to control extensionand retraction of a respective telescopic axle assembly; and a wheelsupport assembly coupled to outboard ends of each of the first andsecond telescopic axle assemblies; wherein the outboard end of the firsttelescopic axle assembly is coupled to the wheel support assembly by alink arm having a first end coupled to the first telescopic axleassembly by a first pivotable connection and a second, opposite endcoupled to the wheel support assembly by a second pivotable connection;and wherein the outboard end of the second telescopic axle assembly iscoupled directly to a crank arm by a third pivotable connection, and thecrank arm is rigidly connected to the wheel support assembly.
 2. Theassembly of claim 1, wherein the first and second telescopic axleassemblies are aligned parallel to one another.
 3. The assembly of claim2, wherein one of the first pivotable connection and the secondpivotable connection comprises a ball-and-socket joint.
 4. The assemblyof claim 1, wherein at least one of the first and second telescopic axleassemblies comprises an outer axle portion and an inner axle portionslideably received by the outer axle portion.
 5. The assembly of claim4, wherein the outer axle portions of each of the first and secondtelescopic axle assemblies are fixed to the chassis.
 6. The assembly ofclaim 4, wherein the outer axle portions each comprise a plurality ofbearings secured within an outer tube, wherein the bearings receive andsupport a respective inner axle portion in a sliding relationship. 7.The assembly of claim 6, wherein the bearings each comprise anadjustable pillow block.
 8. The assembly of claim 4, wherein the inneraxle portion comprises a portion of a hydraulic actuator.
 9. Theassembly of claim 8, wherein the hydraulic actuator comprises a pistonconnected to the outer axle portion or the chassis.
 10. The assembly ofclaim 4, wherein the inner axle portion comprises a tubular member, andwherein the respective actuator comprises a hydraulic actuator connectedbetween the tubular member and the outer axle portion.
 11. The assemblyof claim 10, wherein the hydraulic actuator is mounted to an outsidesurface of the tubular member.
 12. The assembly of claim 1, wherein eachof the first and second telescopic axle assemblies are configured totransfer a portion of a weight of the chassis to the wheel supportassembly.
 13. The assembly of claim 1, wherein the first telescopic axleassembly is rigidly fixed to the second telescopic axle assembly.
 14. Autility vehicle comprising: a chassis; and a plurality of wheel-mountingassemblies coupled to the chassis, each wheel-mounting assemblycomprising: first and second telescopic axle assemblies laterally spacedfrom one another and each secured to the chassis, wherein the first andsecond telescopic axle assemblies each comprise an actuator arranged tocontrol extension and retraction of a respective telescopic axleassembly; and a wheel support assembly coupled to outboard ends of eachof the first and second telescopic axle assemblies; wherein the outboardend of each first telescopic axle assembly is coupled to a respectivewheel support assembly by a link arm having a first end coupled to thefirst telescopic axle assembly by a first pivotable connection and asecond, opposite end coupled to the respective wheel support assembly bya second pivotable connection; and wherein the outboard end of eachsecond telescopic axle assembly is coupled directly to a crank arm by athird pivotable connection, and the crank arm is rigidly connected tothe respective wheel support assembly.
 15. The utility vehicle of claim14, further comprising a steering control system arranged to controlsteering movement of the wheel support assembly with respect to thechassis, wherein, in response to a steering control command, thesteering control system is configured to simultaneously extend a firstof the actuators and retract a second of the actuators so as to pivotthe wheel support assembly around a steering axis.
 16. The utilityvehicle of claim 15, wherein, in response to a track-increase command,the steering control system is configured to simultaneously extend bothactuators to move the wheel support assembly further from the chassis.17. The utility vehicle of claim 14, wherein the utility vehiclecomprises a self-propelled agricultural sprayer.
 18. A method ofadjusting a track width of a utility vehicle, the method comprising:providing a utility vehicle comprising: a chassis; and a plurality ofwheel-mounting assemblies coupled to the chassis, each wheel-mountingassembly comprising: first and second telescopic axle assemblieslaterally spaced from one another and each secured to the chassis,wherein the first and second telescopic axle assemblies each comprise anactuator arranged to control extension and retraction of a respectivetelescopic axle assembly; and a wheel support assembly coupled tooutboard ends of each of the first and second telescopic axleassemblies; wherein the outboard end of each first telescopic axleassembly is coupled to a respective wheel support assembly by a link armhaving a first end coupled to the first telescopic axle assembly by afirst pivotable connection and a second, opposite end coupled to therespective wheel support assembly by a second pivotable connection; andwherein the outboard end of each second telescopic axle assembly iscoupled directly to a crank arm by a third pivotable connection, and thecrank arm is rigidly connected to the respective wheel support assembly;simultaneously extending the first and second telescopic axle assembliessecured to a first wheel support assembly; and simultaneously extendingthe first and second telescopic axle assemblies secured to a secondwheel support assembly.
 19. The method of claim 18, further comprising:maintaining the first and second telescopic axle assemblies secured tothe first wheel support assembly parallel to one another; andmaintaining the first and second telescopic axle assemblies secured tothe first wheel support assembly parallel to one another.